This invention relates to a working vehicle having a speed maintaining apparatus.
In a speed maintaining construction of a conventional working vehicle, a control member is displaced, in response to a pivoting to a retreat position of a speed setting lever, to a position deviating from a pivoting range of a relay rocking element linked to a stepless transmission. This cancels a speed set by the speed maintaining apparatus, and permits a change speed pedal to shift the stepless transmission for forward drive speeds and backward drive speeds.
It has been considered, with the conventional apparatus, to set the retreat position of the speed setting lever to a position very remote in a forward drive decelerating direction (backward drive accelerating direction) from a forward speed setting range of the speed setting lever so that, when the speed setting lever is operated to the retreat position, the control member deviate from the pivoting range of the relay rocking element in the pivoting direction of the relay rocking element, or to set the retreat position of the speed setting lever to a position displaced leftward or rightward from the forward speed setting range of the speed setting lever so that, when the speed setting lever is operated to the retreat position, the control member deviate from the pivoting range of the relay rocking element in a direction perpendicular to the pivoting direction of the relay rocking element (see, for example, Japanese Patent Applications “Kokai” No. 2004-211776 and “Kokai” No. 2001-82597).
In the above prior art, where the retreat position of the speed setting lever is set to a position very remote in the forward drive decelerating direction from the forward speed setting range of the speed setting lever, it is necessary to secure, as the operating range of the speed setting lever, on a limited lever guide, not only the forward speed setting range but also a range for forming space between the relay rocking element and control member for allowing pivoting of the relay rocking element interlocked with a backward drive shifting of the stepless transmission by the change speed pedal. This greatly restricts the forward speed setting range on the lever guide. Where an operating angle of the speed setting lever is made large in order to facilitate precise speed setting for effective operation of the speed setting lever, the speed setting lever must be shortened correspondingly, which will require a strong operating force. Conversely, where the speed setting lever is formed long in order to reduce the operating force, the operating angle of the speed setting lever will become correspondingly small, making it difficult to effect precise speed setting.
On the other hand, where the retreat position of the speed setting lever is set to a position displaced leftward or rightward from the forward speed setting range of the speed setting lever, the speed setting lever must be made pivotable transversely as well as in the fore and aft direction. This leads to a complication of the construction.